diff options
author | Hans Wennborg <hans@hanshq.net> | 2018-01-30 09:48:42 +0000 |
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committer | Hans Wennborg <hans@hanshq.net> | 2018-01-30 09:48:42 +0000 |
commit | 6148a4925e2eef4a34f61c9f379bb81d61e8eac1 (patch) | |
tree | 8141c9fc18ae81cdf9918cd7c1155e4e631d187a /include/llvm | |
parent | 98b79f2cd78d57b8e5f5307ac889fa264cddcc36 (diff) |
Merging r323331:
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r323331 | spatel | 2018-01-24 16:20:37 +0100 (Wed, 24 Jan 2018) | 21 lines
[ValueTracking] add recursion depth param to matchSelectPattern
We're getting bug reports:
https://bugs.llvm.org/show_bug.cgi?id=35807
https://bugs.llvm.org/show_bug.cgi?id=35840
https://bugs.llvm.org/show_bug.cgi?id=36045
...where we blow up the stack in value tracking because other passes are sending
in selects that have an operand that is itself the select.
We don't currently have a reliable way to avoid analyzing dead code that may take
non-standard forms, so bail out when things go too far.
This mimics the recursion depth limitations in other parts of value tracking.
Unfortunately, this pushes the underlying problems for other passes (jump-threading,
simplifycfg, correlated-propagation) into hiding. If someone wants to uncover those
again, the first draft of this patch on Phab would do that (it would assert rather
than bail out).
Differential Revision: https://reviews.llvm.org/D42442
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_60@323737 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'include/llvm')
-rw-r--r-- | include/llvm/Analysis/ValueTracking.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/llvm/Analysis/ValueTracking.h b/include/llvm/Analysis/ValueTracking.h index 1c51523b157..1fdb3cff537 100644 --- a/include/llvm/Analysis/ValueTracking.h +++ b/include/llvm/Analysis/ValueTracking.h @@ -508,7 +508,8 @@ class Value; /// -> LHS = %a, RHS = i32 4, *CastOp = Instruction::SExt /// SelectPatternResult matchSelectPattern(Value *V, Value *&LHS, Value *&RHS, - Instruction::CastOps *CastOp = nullptr); + Instruction::CastOps *CastOp = nullptr, + unsigned Depth = 0); inline SelectPatternResult matchSelectPattern(const Value *V, const Value *&LHS, const Value *&RHS, Instruction::CastOps *CastOp = nullptr) { |